I am having the same or a similar error. I had a previous install of MySQL 5.5 and I had used the default port of 3306. When I did the XAMPP install it installed another instance of MySQL with a separate process. This was not an issue, since I just wanted the XAMPP version for testing without any passwords. I went through EVERY file that referenced port 3306 and changed it to 3307. Nevertheless, myPHPadmin continued to see MySQL as being installed and running on port 3306. When I tried to run the SQL admin tool in the XAMPP startup screen, I got a similar issue. I believe it is directly caused by it (Apache?) continuing to try to connect to my password protected version of MySQL running on port 3306. Since I did not supply it with a password for "root", it will not connect.